Human Genetics

Lab 29: Human Genetics

Jianyi Chen

Section 022

Introduction        

        Taste is one of the five special senses humans’ have, and when tasting, different chemicals react with the taste receptors that are located on the taste buds. Phenylthiocarbamide (PTC) has the unusual property that either tastes very bitter or tasteless, and was discovered by a chemist named Arthur Fox due a powder accident during a lab. After this discovery, the PTC gene was discovered, and the ability or inability to taste PTC is by a single gene in the tongue that codes for a taste receptor (Howard Hughes Medical Institute, 2015). There are some that are non-tasters, regular tasters, and some that are super tasters because everyone perceive taste differently. Non-tasters have fewer taste buds which means fewer taste receptors, super tasters have a lot of taste receptors, and regular tasters is the average between a non-taster and a super taster (Schartow, 2011). For super tasters, the taste receptors are more likely to amplify the taste than non-tasters, therefore, when tasting PTC, super tasters will have a much more bitter taste than regular and non-tasters.

        Linda Bartoshuk is the first to identify “supertasters” and how taste reflects from how many fungiform papillae are present no the tongue; the more fungiform papillae is present the more sensitive you are to taste. In order to taste, the tongue much have taste receptors. Fungiform Papillae are the red dots that are scattered amongst the tongue that contains many of these taste receptors which perceives the taste (Schartow, 2011).

        The question is ‘is being a super taster related to fungiform density?’ The hypothesis is that if a person is a super taster, they will have more fungiform papillae. The prediction is that super tasters will have more fungiform papillae counted in the circle than regular tasters.

Methods

        The methods that were used for this lab were followed by the lab manual Fundamental of Life Science Lab Manual, 2014 by Brenda Leady. There were no changes in the protocol. People were identified as non-tasters, regular taster, and super tasters with the PTC sensitivity. If the PTC paper taste like nothing then it indicates that that person is a non-taster, if it somewhat tastes bitter then it indicates they were a regular taster, and if it tasted extremely bitter than that person is a super taster. To make sure the results were no biased, the tongue was dyed with blue food coloring, and dyed part of the tongue is sectioned out with a card stock so that the papillae can be counted.

Results[pic 1]

The results are above in a bar graph form. There were no data obtained for non-tasters. As for regular tasters, the average is 12 fungiform papillae and about 24 fungiform papillae for super tasters. The data shows that super tasters have more fungiform papillae than regular tasters.

Discussion/Conclusion

        The question is ‘is being a super taster related to fungiform density?’ The hypothesis is that if a person is a super taster, they will have more fungiform papillae. The prediction is that super tasters will have more fungiform papillae counted in the circle than regular tasters. Being a super taster is related to fungiform density because when a person has more fungiform papillae, they are able to taste the PTC as a more bitter taste than a regular or non-taster.

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